A/c control by SIM card

jj_alukkas

Joined Jan 8, 2009
753
Google for 'phone controlled device circuit' or 'SMS controlled device circuit' on google. I had found a good link 2 weeks back using a PIC and a SE 230 cellphone. However you must have the PIC programmer and support softwares to do all this.


This one is based on DTMF, meaning you can even use it with a landline. You call to that number and press the code.
http://ashishrd.blogspot.com/2007/07/cell-phone-controlled-door-latch.html

This based on SMS, but you will need a dedicated cellphone with sim on the recieving device.
http://www.serasidis.gr/circuits/smscontroller/smscontroller.htm
 
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Steve C

Joined Nov 29, 2008
88
I've been looking into this for a long time and havent found a "good" system yet. By good I mean without a monthly cost or hundreds of dollars equipment fee.

Best ive found so far is a bluetooth relay bank. Cheapest I've seen them is $250 to $300. Nice about these is that some can be set to autodetect your presence and activate outputs immediately.

For just one function you can get by with a backlight sensor on a cellphone for CHEAP, but you still need to pay for service. Doesnt use minutes, but you do need a number. And prepay cards don't last forever.

One day.

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Have you considered repurposing a bluetooth headset? If you find a bluetooth headset that does something like blink an LED when your phone pairs, then you should be able to do it real cheap. The LED blink will correspond to a digital signal you can use to latch a relay or talk to a micro or whatever you need to get your switching done.

For manual control you turn bluetooth pairing off for that device. For automatic function you set it to autopair. When you leave your house it should turn the a/c off automatically. As long as you arent just in your driveway or something. BT antennas can have a pretty crazy range.
 

jj_alukkas

Joined Jan 8, 2009
753
The DTMF solves all that problem if you have a landline at home. If you press the activation code while ringing, the circuit activates, otherwise your phone rings as usual. I'm not sure if the above link is like that, but I have seen lots of them online. You need just one DTMF decoder IC or a microcontroller.

And for the SMS type, here in India, we get a prepaid sim with 7 yrs validity without recharge balance for that time period sometimes free or a maximum of Indian Equivalent of 1$. A cheap second hand phone can be obtained for as less as $8 or even less.
 
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